1. Field of the Invention
The present invention relates to a technology for creating speech recognition dictionaries.
2. Related Background Art
Along with the improvement made over speech recognition performance, applications equipped with a speech recognition function that allows creation of electronic mails by voice input have been commercialized. The mainstream of the present speech recognition is a method in which only words registered in a speech recognition dictionary are subject to speech recognition. According to this method, words that do not exist in the speech recognition dictionary (unknown words), in principle, cannot be recognized. Many of the speech recognition software for dictation are equipped with a speech recognition dictionary containing several ten thousands to several hundred thousands base words, which do not necessarily include all the words that are needed by individual users.
As one of the solutions to the above, many of the commercially available speech recognition applications are equipped with a function to allow the user to additionally register words to an existing speech recognition dictionary to update the speech recognition dictionary, or a function to allow the user to create a speech recognition dictionary for the user's personal use. The following methods have been realized for registering words: (1) a method in which information for words to be registered, such as, a notation of each word and a pronunciation of each word to be registered, are inputted word by word by the user; and (2) a method in which an application automatically performs all the necessary processings for word registration when the user merely designates a text that contains words to be registered.
In the latter method (2), for example, unknown words are extracted from a text, and pronunciations are appended to the extracted words, which are then added to a speech recognition dictionary. Words that are once registered may generally be retained until the user deletes them from the speech recognition dictionary.
However, electronic mails may generally contain substantially different written contents depending on topics to be discussed, such that words used in writing electronic mails frequently change from one mail to the other. As a result, when electronic mails are created by using speech recognition, words that are not included in a speech recognition dictionary would likely appear in high probability whenever topics changes, and it is assumed that the speech recognition dictionary would have to be updated in many occasions.
When a speech recognition dictionary is updated according to the method (1) described above, the user needs to input notations and pronunciations for words one by one, which is very onerous when there are many words to be registered as a result of changes of the topics. In contrast, the speech recognition dictionary can be more easily updated by the use of the method (2).